Bacteria hijack a meningeal neuroimmune axis to facilitate brain invasion.

The meninges are densely innervated by nociceptive sensory neurons that mediate pain and headache1,2. Bacterial meningitis causes life-threatening infections of the meninges and central nervous system, affecting more than 2.5 million people a year3-5. How pain and neuroimmune interactions impact meningeal antibacterial host defences are unclear. Here we show that Nav1.8+ nociceptors signal to immune cells in the meninges through the neuropeptide calcitonin gene-related peptide (CGRP) during infection. This neuroimmune axis inhibits host defences and exacerbates bacterial meningitis. Nociceptor neuron ablation reduced meningeal and brain invasion by two bacterial pathogens: Streptococcus pneumoniae and Streptococcus agalactiae. S. pneumoniae activated nociceptors through its pore-forming toxin pneumolysin to release CGRP from nerve terminals. CGRP acted through receptor activity modifying protein 1 (RAMP1) on meningeal macrophages to polarize their transcriptional responses, suppressing macrophage chemokine expression, neutrophil recruitment and dural antimicrobial defences. Macrophage-specific RAMP1 deficiency or pharmacological blockade of RAMP1 enhanced immune responses and bacterial clearance in the meninges and brain. Therefore, bacteria hijack CGRP-RAMP1 signalling in meningeal macrophages to facilitate brain invasion. Targeting this neuroimmune axis in the meninges can enhance host defences and potentially produce treatments for bacterial meningitis.

Group B Streptococcus transcriptome when interacting with brain endothelial cells.

Bacterial meningitis is a life-threatening infection of the central nervous system (CNS) that occurs when bacteria are able to cross the blood-brain barrier (BBB) or the meningeal-cerebrospinal fluid barrier (mBCSFB). The BBB and mBCSFB comprise highly specialized brain endothelial cells (BECs) that typically restrict pathogen entry. Group B Streptococcus (GBS or Streptococcus agalactiae) is the leading cause of neonatal meningitis. Until recently, identification of GBS virulence factors has relied on genetic screening approaches. Instead, we here conducted RNA-seq analysis on GBS when interacting with induced pluripotent stem cell-derived BECs (iBECs) to pinpoint virulence-associated genes. Of the 2,068 annotated protein-coding genes of GBS, 430 transcripts displayed significant changes in expression after interacting with BECs. Notably, we found that the majority of differentially expressed GBS transcripts were downregulated (360 genes) during infection of iBECs. Interestingly, codY, encoding a pleiotropic transcriptional repressor in low-G + C Gram-positive bacteria, was identified as being highly downregulated. We conducted qPCR to confirm the codY downregulation observed via RNA-seq during the GBS-iBEC interaction and obtained codY mutants in three different GBS background parental strains. As anticipated from the RNA-seq results, the [Formula: see text]codY strains were more adherent and invasive in two in vitro BEC models. Together, this demonstrates the utility of RNA-seq during the BEC interaction to identify GBS virulence modulators. IMPORTANCE: Group B Streptococcus (GBS) meningitis remains the leading cause of neonatal meningitis. Research work has identified surface factors and two-component systems that contribute to GBS disruption of the blood-brain barrier (BBB). These discoveries often relied on genetic screening approaches. Here, we provide transcriptomic data describing how GBS changes its transcriptome when interacting with brain endothelial cells. Additionally, we have phenotypically validated these data by obtaining mutants of a select regulator that is highly down-regulated during infection and testing on our BBB model. This work provides the research field with a validated data set that can provide an insight into potential pathways that GBS requires to interact with the BBB and open the door to new discoveries.

Otitis in Patients With Community-Acquired Bacterial Meningitis: A Nationwide Prospective Cohort Study.

BACKGROUND: Otitis is commonly associated with community-acquired bacterial meningitis, but the role of ear surgery as treatment is debated. In this study, we investigated the impact of otitis and ear surgery on outcome of adults with community-acquired bacterial meningitis. METHODS: We analyzed episodes of adults with community-acquired bacterial meningitis from a nationwide prospective cohort study in the Netherlands, between March 2006 and July 2021. RESULTS: A total of 2548 episodes of community-acquired bacterial meningitis were evaluated. Otitis was present in 696 episodes (27%). In these patients the primary causative pathogen was Streptococcus pneumoniae (615 of 696 [88%]), followed by Streptococcus pyogenes (5%) and Haemophilus influenzae (4%). In 519 of 632 otitis episodes (82%) an ear-nose-throat specialist was consulted, and surgery was performed in 287 of 519 (55%). The types of surgery performed were myringotomy with ventilation tube insertion in 110 of 287 episodes (38%), mastoidectomy in 103 of 287 (36%), and myringotomy alone in 74 of 287 (26%). Unfavorable outcome occurred in 210 of 696 episodes (30%) and in 65 of 696 episodes was fatal (9%). Otitis was associated with a favorable outcome in a multivariable analysis (odds ratio 0.74; 95% confidence interval [CI] .59-.92; P = .008). There was no association between outcome and ear surgery. CONCLUSIONS: Otitis is a common focus of infection in community-acquired bacterial meningitis in adults, with S. pneumoniae being the most common causative pathogen. Presence of otitis is associated with a favorable outcome. Ear surgery's impact on the outcome of otogenic meningitis patients remains uncertain.

Successful Treatment of Carbapenem-Resistant Acinetobacter baumannii Meningitis With Sulbactam-Durlobactam.

BACKGROUND: The treatment of carbapenem-resistant Acinetobacter baumannii/calcoaceticus complex (CRAB) presents significant treatment challenges. METHODS: We report the case of a 42-year-old woman with CRAB meningitis who experienced persistently positive cerebrospinal fluid (CSF) cultures for 13 days despite treatment with high-dose ampicillin-sulbactam and cefiderocol. On day 13, she was transitioned to sulbactam-durlobactam and meropenem; 4 subsequent CSF cultures remained negative. After 14 days of sulbactam-durlobactam, she was cured of infection. Whole genome sequencing investigations identified putative mechanisms that contributed to the reduced cefiderocol susceptibility observed during cefiderocol therapy. Blood and CSF samples were collected pre-dose and 3-hours post initiation of a sulbactam-durlobactam infusion. RESULTS: The CRAB isolate belonged to sequence type 2. An acquired blaOXA-23 and an intrinsic blaOXA-51-like (ie, blaOXA-66) carbapenemase gene were identified. The paradoxical effect (ie, no growth at lower cefiderocol dilutions but growth at higher dilutions) was observed by broth microdilution after 8 days of cefiderocol exposure but not by disk diffusion. Potential markers of resistance to cefiderocol included mutations in the start codon of piuA and piuC iron transport genes and an A515V substitution in PBP3, the primary target of cefiderocol. Sulbactam and durlobactam were detected in CSF at both timepoints, indicating CSF penetration. CONCLUSIONS: This case describes successful treatment of refractory CRAB meningitis with the administration of sulbactam-durlobactam and meropenem and highlights the need to be cognizant of the paradoxical effect that can be observed with broth microdilution testing of CRAB isolates with cefiderocol.

Integrating DNA/RNA microbe detection and host response for accurate diagnosis, treatment and prognosis of childhood infectious meningitis and encephalitis.

BACKGROUND: Infectious meningitis/encephalitis (IM) is a severe neurological disease that can be caused by bacterial, viral, and fungal pathogens. IM suffers high morbidity, mortality, and sequelae in childhood. Metagenomic next-generation sequencing (mNGS) can potentially improve IM outcomes by sequencing both pathogen and host responses and increasing the diagnosis accuracy. METHODS: Here we developed an optimized mNGS pipeline named comprehensive mNGS (c-mNGS) to monitor DNA/RNA pathogens and host responses simultaneously and applied it to 142 cerebrospinal fluid samples. According to retrospective diagnosis, these samples were classified into three categories: confirmed infectious meningitis/encephalitis (CIM), suspected infectious meningitis/encephalitis (SIM), and noninfectious controls (CTRL). RESULTS: Our pipeline outperformed conventional methods and identified RNA viruses such as Echovirus E30 and etiologic pathogens such as HHV-7, which would not be clinically identified via conventional methods. Based on the results of the c-mNGS pipeline, we successfully detected antibiotic resistance genes related to common antibiotics for treating Escherichia coli, Acinetobacter baumannii, and Group B Streptococcus. Further, we identified differentially expressed genes in hosts of bacterial meningitis (BM) and viral meningitis/encephalitis (VM). We used these genes to build a machine-learning model to pinpoint sample contaminations. Similarly, we also built a model to predict poor prognosis in BM. CONCLUSIONS: This study developed an mNGS-based pipeline for IM which measures both DNA/RNA pathogens and host gene expression in a single assay. The pipeline allows detecting more viruses, predicting antibiotic resistance, pinpointing contaminations, and evaluating prognosis. Given the comparable cost to conventional mNGS, our pipeline can become a routine test for IM.

SssP1, a Fimbria-like component of Streptococcus suis, binds to the vimentin of host cells and contributes to bacterial meningitis.

Streptococcus suis (S. suis) is one of the important pathogens that cause bacterial meningitis in pigs and humans. Evading host immune defences and penetrating the blood-brain barrier (BBB) are the preconditions for S. suis to cause meningitis, while the underlying mechanisms during these pathogenic processes are not fully understood. By detecting the red blood and white blood cells counts, IL-8 expression, and the pathological injury of brain in a mouse infection model, a serine-rich repeat (SRR) glycoprotein, designated as SssP1, was identified as a critical facilitator in the process of causing meningitis in this study. SssP1 was exported to assemble a fimbria-like component, thus contributed to the bacterial adhesion to and invasion into human brain microvascular endothelial cells (HBMECs), and activates the host inflammatory response during meningitis but is not involved in the actin cytoskeleton rearrangement and the disruption of tight junctions. Furthermore, the deletion of sssP1 significantly attenuates the ability of S. suis to traverse the BBB in vivo and in vitro. A pull-down analysis identified vimentin as the potential receptors of SssP1 during meningitis and following Far-Western blot results confirmed this ligand-receptor binding mediated by the NR2 (the second nonrepeat region) region of SssP1. The co-localisation of vimentin and S. suis observed by laser scanning confocal microscopy with multiplex fluorescence indicated that vimentin significantly enhances the interaction between SssP1 and BBB. Further study identified that the NR216-781 and NR1711-2214 fragments of SssP1 play critical roles to bind to the BBB depending on the sialylation of vimentin, and this binding is significantly attenuated when the antiserum of NR216-781 or NR1711-2214 blocked the bacterial cells, or the vimentin antibody blocked the BBB. Similar binding attenuations are observed when the bacterial cells were preincubated with the vimentin, or the BBB was preincubated with the recombinant protein NR216-781, NR1711-2214 or sialidase. In conclusion, these results reveal a novel receptor-ligand interaction that enhances adhesion to and penetration of the BBB to cause bacterial meningitis in the S. suis infection and highlight the importance of vimentin in host-pathogen interactions.

Group A Streptococcal meningitis in children: a short case series and systematic review.

BACKGROUND: Group A streptococcal(GAS) meningitis is a severe disease with a high case fatality rate. In the era of increasing GAS meningitis, our understanding about this disease is limited. PURPOSE: To gain a better understanding about GAS meningitis. METHODS: Five new cases with GAS meningitis were reported. GAS meningitis related literatures were searched for systematic review in PUBMED and EMBASE. Case reports and case series on paediatric cases were included. Information on demographics, risk factors, symptoms, treatments, outcomes, and emm types of GAS was summarized. RESULTS: Totally 263 cases were included. Among 100 individuals, 9.9% (8/81) had prior varicella, 11.1% (9/81) had anatomical factors, and 53.2% (42/79) had extracranial infections. Soft tissue infections were common among infants (10/29, 34.5%), while ear/sinus infections were more prevalent in children ≥ 3 years (21/42, 50.0%). The overall case fatality rate (CFR) was 16.2% (12/74). High risk of death was found in patients with shock or systemic complications, young children(< 3 years) and cases related to hematogenic spread. The predominate cause of death was shock(6/8). Among the 163 patients included in case series studies, ear/sinus infections ranged from 21.4 to 62.5%, while STSS/shock ranged from 12.5 to 35.7%, and the CFR ranged from 5.9 to 42.9%. CONCLUSIONS: A history of varicella, soft tissue infections, parameningeal infections and CSF leaks are important clinical clues to GAS in children with meningitis. Young children and hematogenic spread related cases need to be closely monitored for shock due to the high risk of death.

Epidemiology and antimicrobial resistance patterns of bacterial meningitis among hospitalized patients at a tertiary care hospital in Saudi Arabia: a six-year retrospective study.

INTRODUCTION: Bacterial meningitis poses significant medical challenges due to its acute inflammatory nature and potential for severe neurological complications, emphasizing the need for prompt diagnosis and treatment. Limited data exists on its epidemiology and antimicrobial resistance trends among hospitalized patients in Saudi Arabia. This study aimed to investigate these factors at a tertiary care hospital over six years. METHODS: A retrospective analysis was conducted on cerebrospinal fluid samples results from 222 bacterial meningitis cases among hospitalized patients between 2018 and 2023. Demographic, clinical, microbiological data, and antibiotic susceptibility patterns were collected and analyzed. RESULTS: Pseudomonas aeruginosa (43%) was the predominant pathogen isolated. Neonates (16%) and children (47%) were most affected population. Nosocomial meningitis accounted for 92% of cases, mainly in the intensive care settings (50.45%). Extended-spectrum beta-lactamase was the leading resistance pattern (12.2%). Seasonal variation was observed, with a peak incidence in October-November. CONCLUSION: The study highlights the substantial burden of bacterial meningitis among hospitalized patients, especially among high-risk groups. Emerging antimicrobial resistance emphasizes the need for optimized surveillance and stewardship. Future prospective research employing molecular techniques across multiple centers in the country is warranted to enhance understanding and guide public health strategies in Saudi Arabia.

How common is otogenic meningitis? A retrospective study in southern Sweden over 18 years.

BACKGROUND: Bacterial meningitis is a rare, but life-threatening disease, which sometimes occurs as a complication to acute otitis media (AOM). The proportion of meningitis cases originating from AOM is not clear. PURPOSE: The aim of this study was to investigate the proportion of meningitis cases caused by AOM, to compare risk factors, bacteriology and outcome between otogenic and non-otogenic meningitis, and to analyse the incidence of bacterial meningitis after the introduction of conjugate pneumococcal vaccines (PCV). METHODS: The medical charts of all patients admitted to hospitals in southern Sweden with bacterial meningitis between 2000 and 2017 were retrieved. Based on otoscopy and/or imaging, the proportion of otogenic meningitis cases was calculated, as were annual incidences. RESULTS: A total of 216 patients were identified, 25 of whom died. The proportion of otogenic meningitis was 31% but varied from 6% among teenagers to 40% among adults. Before PCV, 23% of all meningitis cases were children < 2 years, compared to 1% post-PCV. The average incidence in the adult population, on the other hand, increased post-PCV, though there were large annual variations. S. pneumoniae was the most commonly identified pathogen in everyone but teenagers, in whom N. meningitidis was predominant. CONCLUSION: AOM is an important cause of meningitis in children and adults. Though bacterial meningitis almost disappeared in children < 2 years after the introduction of PCV, the incidence of pneumococcal meningitis in adults seems to have increased.

Clinical characteristics and antimicrobial therapy of healthcare-associated carbapenem-non-susceptible gram-negative bacterial meningitis: a 16-year retrospective cohort study.

OBJECTIVE: Healthcare-associated Gram-negative bacterial meningitis is a substantial clinical issue with poor outcomes, especially for neurosurgical patients. Here, we aimed to study the characteristics and treatment options of patients with healthcare-associated carbapenem-non-susceptible (Carba-NS) Gram-negative bacterial meningitis. METHODS: This observational cohort study was conducted at a teaching hospital from 2004 to 2019. The clinical characteristics of patients with meningitis with Carba-NS and carbapenem-susceptible (Carba-S) bacilli were compared, and the antimicrobial chemotherapy regimens and outcomes for Carba-NS Gram-negative bacterial meningitis were analyzed. RESULTS: A total of 505 patients were included, of whom 83.8% were post-neurosurgical patients. The most common isolates were Acinetobacter spp. and Klebsiella spp., which had meropenem-resistance rates of 50.6% and 42.5%, respectively, and showed a markedly growing carbapenem-resistance trend. Kaplan-Meier curve analysis revealed that Carba-NS Gram-negative bacilli were associated with a significantly higher in-hospital mortality rate (18.8%, 35/186) compared to the Carba-S group (7.4%, 9/122; P = 0.001). For Carba-NS Enterobacterales meningitis, aminoglycoside-based and trimethoprim-sulfamethoxazole-based regimens yielded significantly higher clinical efficacy rates than non-aminoglycoside-based and non-trimethoprim-sulfamethoxazole-based regimens (69.0% vs. 38.7%, P = 0.019 and 81.8% vs. 46.9%, P = 0.036, respectively). For Carba-NS A. baumannii complex meningitis, tetracycline-based (including doxycycline, minocycline, or tigecycline) therapy achieved a significantly higher clinical efficacy rate (62.9%, 22/35) than the non-tetracycline-based therapy group (40.4%, 19/47; P = 0.044). CONCLUSIONS: Our findings revealed that Carba-NS Gram-negative bacilli are associated with higher in-hospital mortality in patients with healthcare-associated meningitis. The combination therapies involving particular old antibiotics may improve patients' outcome. TRIAL REGISTRATION: This study was registered on the Chinese Clinical Trial Register under ChiCTR2000036572 (08/2020).

Clinical and pathological features of cerebrospinal meningitis caused by Pantoea agglomerans : a case report.

BACKGROUND: Pantoea agglomerans (P. agglomerans) is a gram-negative bacterium that is commonly isolated from plant surfaces, seeds, and the environment. As an opportunistic pathogen, it can cause blood, urinary and soft tissue infections in immunocompromised patients. In central nervous system, P. agglomerans infection has been report in children and immune-compromised patients, however, infection by such bacterium in nontraumatized immune competent adults has not been reported. Here, we report a case of P. agglomerans cerebrospinal meningitis accompanied by positive anti-myeloperoxidase (MPO) antibody in a 49-year-old female who has a history of black fungus planting. CASE PRESENTATION: The patient manifested with repeated fever, headache, generalized muscle pain, and neurological defects. Cerebrospinal fluid (CSF) tests revealed a moderately elevated number of polymorphonuclear leukocytes (50-193 × 106/L), low glucose levels (0.54-2.44 mmo1/L), and extremely high protein content (2.42-25.42 g/L). Blood tests showed positive anti-myeloperoxidase antibodies lasting for 1.5 year before turning negative. Spine MRI showed thickening and enhancement of the whole spinal meninges. CSF metagenomic next-generation sequencing (mNGS) revealed 75,189 specific DNA reads of P. agglomerans. The patient underwent spinal laminectomy due to meningeal adhesions. Pathological results revealed fibrous tissue proliferation, inflammatory infiltration with focal necrosis and calcification in the dura mater. The patient was successfully treated with sufficient antibiotics at 1-year follow-up. CONCLUSIONS: People should be alert to CNS infections caused by P. agglomerans which presented with relatively mild clinical symptoms at onset, especially for those who contucts relevant agricultural and forestry work. The CSF characterization of P. agglomerans meningitis is elevated multiple nuclei white blood cells, significantly reduced glucose content, and markedly increased protein level which may be related to the secondary spinal membrane adhesions.

Diagnosis and management of bacterial meningitis in adult Sudanese patients: a six years hospital based, retrospective, cross-sectional study.

PURPOSE: To evaluate the diagnosis and management of bacterial meningitis in adult Sudanese patients in accordance with the Infectious Diseases Society of America (IDSA) guidelines for bacterial meningitis management. PATIENTS AND METHODS: A cross-sectional, retrospective study design was used to recruit all patients aged > 18 years who were diagnosed with or suspected of having bacterial meningitis and admitted to Wad Medani Teaching Hospital, Gezira State, Sudan, between January 2017 and October 2022. RESULTS: In total, 201 patients were included in the analysis. The mean age of the participants was 44.1 ± 21.4 years, and 107 (53.2%) were male. Community-acquired bacterial meningitis accounted for 193 (96%) of the studied patients, and only 8 (4%) of the patients had healthcare-associated meningitis. Neuroimaging was utilized appropriately in 148 (73.6%) patients, blood cultures were not performed entirely, and lumbar puncture was seldom performed in 1 (0.5%) patient. Corticosteroids were appropriately administered to 65 (32.3%) patients, and antibiotics were administered appropriately to only 5 (2.5%) patients. Ceftriaxone 185 (76.1%) was the most frequently utilized antibiotic, followed by vancomycin 23 (9.5%). In terms of overall adherence, this study demonstrated that the IDSA guidelines were not followed at all in the treatment of patients with suspected bacterial meningitis. CONCLUSION: The results of this study contradict the IDSA guidelines for the standard of care for bacterial meningitis. Antibiotic regimens are often incorrect, corticosteroids are administered appropriately in approximately one-third of patients, and neuroimaging is reasonably utilized. This study raises attention to several important issues regarding the diagnosis of bacterial meningitis, including the lack of confirming microbiological tests and the reliance of the diagnosis primarily on CT and clinical examination.

CARD8 polymorphisms among bacterial meningitis patients in North-West Ethiopia.

BACKGROUND: The severity of infectious disease outcomes is dependent on the virulence factors of the pathogen and the host immune response. CARD8 is a major regulator of the innate immune proinflammatory response and has been suggested to modulate the host response to common inflammatory diseases. In the present study, the C10X genetic polymorphism in the CARD8 gene was investigated in relation to bacterial meningitis. METHODS: A total of 400 clinically suspected meningitis patients hospitalized at the University of Gondar Hospital were enrolled in the study. Cerebrospinal fluid (CSF) and blood samples were collected for laboratory investigations. The collected CSF was cultured, and all the results obtained from the culture were confirmed using direct RT‒PCR. Genotyping of whole-blood samples was performed using a TaqMan assay. The results were compared with apparently healthy controls and with PCR-negative meningitis suspected patients. RESULTS: Of the included patients, 57% were men and the most common clinical signs and symptoms were fever (81%), headache (80%), neck stiffness (76%), nausea (68%), and vomiting (67%). Microbiology culture identified 7 patients with bacterial meningitis caused by Neisseria meningitidis (n = 4) and Streptococcus pneumoniae (n = 3). The RT-PCR revealed 39 positive samples for N. meningitidis (n = 10) and S. pneumoniae (n = 29). A total of 332 whole-blood samples were genotyped with the following results: 151 (45.5%) C10X heterozygotes, 59 (17.7%) C10X homozygotes and 122 (36.7%) wild genotypes. The polymorphic gene carriers among laboratory confirmed, clinically diagnosed meningitis and healthy controls were 23(46%), 246(40%), and 1526(39%), respectively with OR = 1.27 (0.7-2.3) and OR = 1.34 (0.76-2.4). The presence of the C10X polymorphism in the CARD8 gene was more prevalent in suspected meningitis patients than in healthy controls (OR 1.2; 1.00-1.5). Homozygote C10X polymorphic gene carriers were more susceptible to infectious disease. The presence of viable or active bacterial infection was found to be associated with the presence of heterozygous C10X carriers. CONCLUSIONS: A greater proportion of C10X in the CARD8 gene in confirmed bacterial meningitis patients and clinically diagnosed meningitis patients than in healthy controls. Homozygote C10X polymorphic gene carriers were more susceptible to infectious disease than heterozygote gene carriers and healthy controls.

Seronegative brucella meningitis diagnosed by CSF PCR: report on seven cases.

INTRODUCTION: Neurobrucellosis (NB) can be associated with meningitis and present as a headache with or without meningeal signs. Pseudotumor presentation of NB has been reported to be accompanied by lymphocytic predominant cerebrospinal fluid(CSF) pleocytosis. NB is diagnosed by means of isolation of Brucella from blood or CSF and/or the presence of anti-Brucella antibodies in the CSF. Molecular techniques have been used in chronic or challenging cases of NB. CLINICAL FINDINGS: We report on seven cases of NB presenting with different types of headache and signs of meningeal involvement. In five cases, signs of intracranial hypertension were evident in the form of papilledema, sixth nerve palsy and blurred vision. DIAGNOSIS: MRIs of the brain revealed signs of intracranial hypertension in three patients, basal meningeal enhancement in one patient and white matter lesions in one patient. Brucella serology in the blood and CSF was negative in all patients. It was interesting that four patients had normocellular CSF analysis with normal glucose and protein results. The diagnosis was made by Brucella PCR in all patients. CONCLUSION: NB should be considered in the differential diagnoses of pseudotumor cerebri syndrome in endemic areas. It is important to employ molecular techniques using sterile CSF samples in the investigation of Brucella.

Chronic meningitis in adults: a comparison between neurotuberculosis and neurobrucellosis.

BACKGROUND: In regions endemic for tuberculosis and brucellosis, distinguishing between tuberculous meningitis (TBM) and brucella meningitis (BM) poses a substantial challenge. This study investigates the clinical and paraclinical characteristics of patients with TBM and BM. METHODS: Adult patients diagnosed with either TBM or BM who were admitted to two referral hospitals between March 2015 and October 2022, were included, and the characteristics of the patients were analyzed. RESULTS: Seventy patients formed the study group, 28 with TBM and 42 with BM, were included. TBM patients had a 2.06-fold (95% CI: 1.26 to 3.37, P-value: 0.003) higher risk of altered consciousness and a 4.80-fold (95% CI: 1.98 to 11.61, P-value: < 0.001) higher risk of extra-neural involvement as compared to BM patients. Cerebrospinal fluid (CSF) analysis revealed a significantly higher percentage of polymorphonuclear leukocytes (PMN) in TBM compared to BM (Standardized mean difference: 0.69, 95% CI: 0.18 to 1.20, P-value: 0.008). Neuroimaging findings indicated higher risks of hydrocephalus (P-value: 0.002), infarction (P-value: 0.029), and meningeal enhancement (P-value: 0.012) in TBM compared to BM. Moreover, TBM patients had a 67% (95% CI: 21% to 131%, P-value:0.002) longer median length of hospital stay and a significantly higher risk of unfavorable outcomes (Risk ratio: 6.96, 95% CI: 2.65 to 18.26, p < 0.001). CONCLUSIONS: Our study emphasizes that TBM patients displayed increased frequencies of altered consciousness, PMN dominance in CSF, extra-neural involvement, hydrocephalus, meningeal enhancement, and brain infarction. The findings emphasize the diagnostic difficulties and underscore the importance of cautious differentiation between these two conditions to guide appropriate treatment strategies.

Acute multiple brain infarctions associated with Streptococcus suis infection: a case report.

Streptococcus suis is one of the most common zoonotic pathogens, in humans and can cause meningitis, endocarditis, arthritis and sepsis. Human cases of Streptococcus suis infection have been reported worldwide, and most of those cases occurred in Asia. Hearing loss is the most common sequela of Streptococcus suis meningitis. Streptococcus suis infection complicated with acute cerebral infarction has rarely been reported. Therefore, to provide a reference for this disease, we reported a case of acute multiple brain infarctions associated with Streptococcus suis infection. In our report, a 69yearold male patient had Streptococcus suis meningitis and sepsis, which were associated with multiple acute cerebral infarctions in the pons and bilateral frontotemporal parietal occipital lobes. After treatment, the patient exhibited cognitive impairment, dyspraxia and irritability. There are limited case reports of cerebral infarction associated with Streptococcus suis infection, and further research is needed to determine the best treatment method.

Simultaneous Presentation of B-Acute Lymphoblastic Leukemia and Streptococcus agalactiae Meningitis in a 3-Year-old Girl.

Infection is a major cause of treatment-related morbidity and mortality in pediatric acute lymphoblastic leukemia (ALL). Most children with ALL who develop life-threatening bacterial infections do so during induction therapy. We describe a rare case of ALL presenting simultaneously with Streptococcus agalactiae group B Streptococcus bacteremia and meningitis in a 3-year-old girl. She received appropriate antimicrobial therapy and a 2-drug early induction regimen consisting of vincristine and dexamethasone, leading to slow neurologic recovery and a favorable initial response to anti-neoplastic therapy as evidenced by minimal residual disease of 1.12% on day 15 of induction.

Insight into the role of Streptococcus suis zinc metalloprotease C from the new serotype causing meningitis in piglets.

Streptococcus suis (S. suis) is an important gram-positive pathogen and an emerging zoonotic pathogen that causes meningitis in swine and humans. Although several virulence factors have been characterized in S. suis, the underlying mechanisms of pathogenesis are not fully understood. In this study, we identified Zinc metalloproteinase C (ZmpC) probably as a critical virulence factor widely distributed in S. suis strains. ZmpC was identified as a critical facilitator in the development of bacterial meningitis, as evidenced by the detection of increased expression of TNF-α, IL-8, and matrix metalloprotease 9 (MMP-9). Subcellular localization analysis further revealed that ZmpC was localized to the cell wall surface and gelatin zymography analysis showed that ZmpC could cleave human MMP-9. Mice challenge demonstrated that ZmpC provided protection against S. suis CZ130302 (serotype Chz) and ZY05719 (serotype 2) infection. In conclusion, these results reveal that ZmpC plays an important role in promoting CZ130302 to cause mouse meningitis and may be a potential candidate for a S. suis CZ130302 vaccine.

Characterization of meningitis-causing bacteria, with focus on genomic and pangenomic study of multi-drug resistant Streptococcus pneumoniae from cerebrospinal fluid.

Streptococcus pneumoniae is a major cause of meningitis in under developed countries with low vaccination rates and high antibiotic resistance. This study aimed to analyze 83 suspected meningitis patients in Karachi for the detection of S. pneumoniae followed by its whole genome sequencing and Pan Genome analysis. Out of the 83 samples collected, 33 samples with altered physical (turbidity), cytological (white blood cell count) and biochemical (total protein and total glucose concentrations) parameters indicated potential meningitis cases, while these parameters were within normal healthy ranges in remaining 50 samples. Latex particle agglutination (LPA) was performed on the 33 samples, revealing 20 positive cases of bacterial meningitis. The PCR and culturing methods revealed 5 S. pneumoniae isolates. Antibiotic susceptibility tests showed that one S. pneumoniae strain was resistant to erythromycin, levofloxacin, and tetracycline. Whole-genome sequencing of this resistant strain was performed and S. pneumoniae was confirmed with MLST analysis, while it had > 2.3 Mb genome and a single repUS43 plasmid. In CARD analysis, the strain had tet(M), ermB, RlmA(II), patB, pmrA, and patA ARGs, which could provide resistance against tetracycline, macrolide, fluoroquinolone, and glycopeptide antibiotics. Phylogenetic analysis revealed that the isolate was closely related to strains from Hungary and the USA. Pan-genome analysis with 144 genome assemblies from NCBI database showed that 1101 non-redundant core genes were shared between all strains. This study gives valuable understanding into the prevalence and characterization of meningitis-causing bacteria in Karachi, Pakistan  with prime focus on multi-drug resistant S. pneumoniae.